Survival, flowering and productivity of watermelon (Citrullus lanatus) cultivars in inter-generic grafting on nematode-resistant Cucumis seedling rootstocks in Meloidogyne-infested fields

A new procedure for optimising stem diameters of watermelon (Citrullus lanatus) and nematode-resistant wild indigenous Cucumis species suggested that the two genera were highly compatible, with rootstock seedlings retaining their ability to suppress Meloidogyne species. A field study was initiated using the new procedure to determine the influence of inter-generic grafting of Citrullus cultivars onto Cucumis species on survival of grafts, flowering, fruit yield and accumulation of essential nutrient elements under field infested with Meloidogyne species. Four weeks after transplanting, Cucumis africanus and C. myriocarpus rootstocks increased flowering by 70-81% and 96-77% in two watermelon cultivars. At harvest, 66 days after transplanting, rootstocks reduced nematode reproductive factor values by 92-93% and 94-96%, but increased fresh fruit yield by 46-60% and 48-115% and dry shoot weight by 50-66% and 30-104% in watermelon cultivars. Rootstocks had no effect on accumulation abilities of essential nutrient elements in leaves except for Mn and Zn. Inter-generic grafting of Citrullus cultivars onto Cucumis species improved the productivity of the former in areas heavily infested with Meloidogyne species. Thus, inter-generic technology with optimised stem diameters needs to be expanded to other genera where incompatibility challenges had been limiting the use of this technology. © 2012 Friends Science Publishers.status: publishe